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Host plant mediated interactions between gram pod borer, Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae) and its nucleopolyhedrovirus

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Title Host plant mediated interactions between gram pod borer, Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae) and its nucleopolyhedrovirus
 
Creator R, Channakeshava
 
Contributor V. T, Sannaveerappanavar
 
Subject animal developmental stages, planting, vegetables, cotton, land resources, biological phenomena, viruses, chickpeas, pigeonpeas, beans
 
Description Studies were undertaken to ascertain the influence of host plants on virulence of
HearNPV to H.armigera larvae, interactions between phytochemicals and virus,
screening of different isolates, standardization of field doses and selection of suitable
adjuvants to enhance the bio-efficacy of HearNPV. H.armigera larvae reared on field
bean, pigeonpea and chickpea were more susceptible to HearNPV compared to those
reared on tomato and cotton. Larvae reared on cotton and tomato recorded lower yields of
POBs (3.69x107 and 2.19x108 POBs/larva, respectively) compared to fieldbean,
pigeonpea and chickpea (4.64x108, 3.83x108 and 3.12x108 POBs/larva, respectively) at
inoculum dose of 5x104 POBs per ml. The TEM images of POBs recovered from cotton
and tomato leaf surfaces after 48hrs. of contact showed cracks and loss outer coat of
polyhedra. Leaf extracts of cotton, tomato and chickpea caused adverse effect on the
HearNPV with longer LT50 values when POBs were suspended for 48 hrs. The pH of
host plants varied from near neutral (tomato, chickpea) to highly alkaline (cotton). Cotton
and tomato foliage had higher total phenol and tannin contents with higher peroxidase
activity compared to other host plants. The virus persisted for shorter period on cotton
and tomato foliage. Among ten isolates of HearNPV tested, BCRL-1 isolate was highly
virulent with lowest LC50 value (0.03 POBs/mm2). The bio-efficacy studies indicated that
HearNPV at 2.5x1011, 5x1011 and 7.5x1011 POBs/ha was effective in reducing fruit
damage on tomato, whereas on field bean and chickpea it was effective at 5x1011 and
7.5x1011 POBs/ha. Four sprays of HearNPV on pigeonpea at higher doses (1x1012 and
1.5x1012 POBs/ha) were effective in suppressing the pod borer. On cotton, virus was
relatively less effective even at 1x1012 and 1.5x1012 POBs/ha. The adjuvants viz., boric
acid, Robin blue®, egg albumen, Tinopal®, mannitol and ascorbic acid were effective in
preserving the viral activity.
 
Date 2016-05-18T09:10:37Z
2016-05-18T09:10:37Z
2012-08-17
 
Type Thesis
 
Identifier Th-10327
http://krishikosh.egranth.ac.in/handle/1/66042
 
Language en
 
Format application/pdf
 
Publisher University of Agricultural Sciences, Bengaluru